He submitted serious testimony to a judiciary subcommittee hearing on the issue of farm workers and immigration, but when it was his turn to speak, the talk show host slipped into character as a satirical conservative to make his points in support of more favored status for migrant farm laborers.

"This is America," he told the panel. "I don't want a tomato picked by a Mexican," he said. "We do not want immigrants doing this labor."

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He tried to enter images from his colonoscopy into the Congressional Record during a riff on how Americans should eat less roughage. Then Colbert recalled his day spent picking vegetables at an upstate New York farm earlier this summer.

"I'll admit, I started my day with a preconceived notion of immigrant labor," he said.

"I have to say, and I do mean this sincerely: Please don't make me do this again. It is really, really hard," Colbert said, pretending to choke up.

And he didn't stop there.

On the bill dealing with immigrant workers, Colbert quipped, "Like most members of Congress, I haven't read it." He sarcastically expressed confidence that as the bill moves forward, "both sides will work together as you always do."

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That was one of the rare jokes that actually drew a good laugh from the packed committee room.

Colbert then concluded his opening statement by saying, "USA, No. 1."

Rep. John Conyers, D-Mich., the chairman of the House Judiciary Committee, was not amused. "Mr. Colbert's submitted statement was considerably different from the one that he presented," he said.

Colbert's sarcasm continued when he was questioned by lawmakers. Asked by the panel's ranking Republican, Lamar Smith of Texas, how many workers had joined him during his day on the New York farm, Colbert replied, "I didn't take a count. I'm not good at math." When Smith asked how many of them were illegal, Colbert replied, "I didn't ask them for their papers, although I had a strong urge to."

Smith asked Colbert if that one day on the farm made him an expert. Colbert replied, "I believe one day of me studying anything makes me an expert."

And asked if he endorsed GOP policies, Colbert said, "I endorse all Republican policies without question," prompting Smith to thank Colbert for his endorsement of the Republicans' just-unveiled Pledge to America.

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Smith asked if working in the apple orchard was hard work. "It is harder work than this," Colbert shot back, referring to his appearance before Congress.